Power adapter is a power supply widely used in our daily life for converting and providing power to electrical appliances. For being applied to various conditions, generally, the power adapter has a special structure design for assembling. FIG. 1A is an exploded view illustrating a conventional power adapter, and FIG. 1B is a perspective view illustrating the power adapter of FIG. 1A. As shown in FIGS. 1A and 1B, the power adapter 1 includes an upper housing 11, a lower housing 12, a circuit board 13, an electrical connector 14 and a power cord 15. The upper housing 11 and the lower housing 12 are assembled together to define an accommodation space for accommodating the circuit board 13. The electrical connector 14 and the power cord 15 are electrically connected with the circuit board 13 separately and retained by the upper housing 11 and the lower housing 12. A first recess 111 and a second recess (not shown) are respectively formed on the front side and the rear side of the upper housing 11. A third recess 121 and a fourth recess 122 are respectively formed on the front side and the rear side of the lower housing 12. When the upper housing 11 and the lower housing 12 are assembled together, a first hole is defined by the first recess 111 and the third recess 121 for fixing and retaining the electrical connector 14 and a second hole is defined by the second recess and the fourth recess 122 for fixing and retaining a fixing portion 151 of the power cord 15.
The electrical connector 14 includes an insulation body 141 and plural pins 142. The insulation body 141 has an engaging part 143 and a concave 144. The engaging part 143 is extended outwardly from the peripheral surface of the insulation body 141 at the front end. The engaging part 143 has a groove 145 corresponding to the rim of the first recess 111 and the rim of the third recess 121. The pins 142 are located in the concave 144 inside the insulation body 141. Generally, the upper housing 11, the lower housing 12 and the electrical connector 14 are assembled together by ultrasonic welding technology. Since the electrical connector 14 is independent from the upper housing 11 and the lower housing 12, the engaging part 143 of the electrical connector 14 is necessary for engaging with the rim of the first recess 111 and the rim of the third recess 121. Consequently, the electrical connector 14 is fixed in the first hole. However, the above-mentioned engaging structure causes the additional volume of the electrical connector 14 and further affects the dimensions of the power adapter 1. Especially, the thickness h of the power adapter 1 can't be reduced because of the specific size of the electrical connector 14. Namely, the thickness of the power adapter 1 is limited by the size and profile of the electrical connector 14. Consequently, the thinning and the miniaturization of the power adapter 1 are affected. In addition, the power adapter 1 is not easy to be assembled.
Therefore, there is a need of providing a power adapter and an electrical connector module thereof to obviate the drawbacks encountered from the prior arts.